Fig. 1

Sphere culture caused enrichment of CD133 ⁺ population. The morphology of parental SK-UT-1 cells and spheres (magnification, ×200) (a), sphere formation rate of primary sphere and spheres at passages 1–4 on the 6 day (b), the process of formation of spheres derived from the SK-UT-1 cells (magnification, ×400) (c), SK-UT-1 derived-spheres enriched CD133 cells (d). The primary spheres and spheres at passages 1–4 were stained with FITC-conjugated antibody against CD133 and analyzed using a flow cytometer. Data were presented as mean ± SD (n = 3, *P < 0.05)